An oil-in-water (hereinafter referred to as O/W) emulsified fat or oil composition has been known to be featured in that its plasticity is not affected by the hardness of the fat or oil used because the external phase is water, and it has good flavor, nonstickiness, spreadability, etc., and is used for a foaming emulsified composition for confectionery and baking, whipped cream, etc.
However, this O/W emulsified fat or oil composition has drawbacks such that it is apt to cause the growth of microorganisms because its external phase is water.
On the contrary, a water-in-oil (hereinafter referred to as W/O) emulsified fat or oil has heretofore been extensively used for cream, spread, cooking, confectionery, baking, etc.
However, the W/O emulsified fat or oil has a drawback that the fat or oil of the outermost layer must be soft to give improved meltability in the mouth when being used in cream or spread.
In order to improve the drawbacks of the O/W or W/O emulsified fat or oil while realizing their merits, many O.sub.1 /W/O.sub.2 doubly emulsified fat or oil compositions were studied, and many techniques for producing O.sub.1 /W/O.sub.2 doubly emulsified fat or oil compositions having a natural butter-like aftertaste and body were proposed. For example, the use of a flavored fat or oil as the fat or oil to be used in O.sub.1 was proposed in Japanese Patent Laid-Open No. 165736/1983.
However, when the stability of the innermost oil phase O.sub.1 in the initially prepared inner phase O/W emulsion is remarkably poor the fusion of O.sub.1 with O.sub.2 occurs even if the proportions of O.sub.1, W and O.sub.2 k were predetermined, especially in the step of rapid cooling and kneading after emulsifying the O.sub.1 /W emulsion in the O.sub.2. Thus, the amount of remaining O.sub.1 is extremely reduced. As a result, the obtained emulsion is similar to a W/O emulsion, so that it cannot fully exhibit a good taste characteristic of the intended O.sub.1 /W/O.sub.2 doubly emulsified fat or oil composition.
Therefore, it is desired to improve the stability of an O.sub.1 /W emulsion in order to keep the fat or oil globules of O.sub.1 stable without being destroyed and fused with the O.sub.2 fat or oil.
Meanwhile, an oil-in-water-in-oil doubly emulsified fat or oil composition is liable to cause bleeding of water or oil-off during storage, or destruction of emulsion accompanied with the separation of an aqueous phase and spoilage in bulk handling, so that it has not been satisfactorily applied to various fields.
In order to overcome these defects, it has already been proposed to use various emulsifying agents. For example, it has been known to use a sucrose fatty acid ester having an HLB of 1 to 4 (see Japanese Patent Publication No. 10014/1981) or a glycerol fatty acid ester (see U.S. Pat. No. 3,889,005) or to use both of a polyglycerol fatty acid ester and a fatty acid ester having at least 12 carbon atoms together (see Japanese Patent Laid-open No. 170432/1983).
Among the above polyglycerol fatty acid esters, polyglycerol condensed ricinoleic acid ester is particularly excellent in emulsifying power. However, an oil-in-water-in-oil doubly emulsified fat or oil composition prepared by using this ester has a soft, i.e., tasty texture, so that the composition is poor in shape retention and is liable to cause oil-off. Further, the composition is also poor in long-term stability at low temperature to cause separation of an aqueous phase.